This invention relates to electrical switching devices, and more particularly to a device for switching audio signals from one circuit to another without causing any undesirable noise or signal spiking.
In order to introduce unusual sound features into their performances, musicians, and in particular those using electrical guitars, have in the past utilized a so-called A/B box, or similar switching device, for routing the audio signal from the instrument simultaneously or selectively through two different signal paths to an amplifier input, or the like. Typically the box includes two mechanical switches, one of which is operated to control the path of the output signal selectively through one path (A) or the other (B) to an In/Out port; the other of which is operable to route the signals simultaneously through both paths. Moreover, such boxes have also been designed to permit bi-directional routing of such signals to or from the In/Out port. In any case, however, the major disadvantage of such prior devices has been the tendency of the associated switches to generate undesirable signal or voltage spikes in the audio circuits whenever the associated switch is manipulated. The spikes in turn generate loud popping sounds in the associated speaker system; and for this reason boxes or switching devices of the type described have not heretofore achieved widespread acceptance.
It is an object of this invention, therefore, to provide an improved switching device of the type described which substantially eliminates the appearance of any undesirable signal spikes upon the interruption or switching of an audio signal from one circuit to another.
A more specific object of this invention is to provide an improved signal switching device of the type described which is suitable for use in a bi-directional manner for either combining or separating audio signals without introducing any undesirable spikes in the signals.
Other objects in the invention will be appearing hereinafter from the specification and from the recital of the appended claims, particularly when right in conjunction with the company drawing.